In general, a display device collectively refers to monitors for a TV or a computer as a whole, and includes a display device which forms an image and a case supporting the display device.
Examples of the display device may include a plasma display panel (PDP), a liquid crystal display (LCD), an organic light emitting diode (OLED), an electrophoretic display, and a cathode-ray tube (CRT). The display device may include an RGB pixel pattern for implementing an image and an additional optical filter.
The optical filter may include at least one of a reflection prevention film which prevents the external light that is incident from the outside from being reflected to the outside again, a near IR shield film which shields the near IR generated in the display device in order to prevent mis-operation of electronic devices such as remote controllers, a color correction film which increases the color purity by controlling a color tone by including a color control dye, and an electromagnetic wave shield film for shielding the electromagnetic wave generated in a display device when a display apparatus is driven. Here, the electromagnetic wave shield film includes a transparent base substrate and a metal mesh pattern provided on the base substrate.
Meanwhile, with regard to the display apparatus, as the spread of IPTVs is accelerated, a demand for a touch function that uses hands as a direct input apparatus without a separate input apparatus such as remote controllers is growing. Further, a multi-touch function that is capable of recognizing a specific point and writing is also required.
The touch screen sensor which performs the aforementioned function may be classified into the following types according to a detection manner of the signal.
That is, there are a resistive type of sensing a position which is pressed down by pressure through a change in current or voltage value while a direct current voltage is applied thereto, a capacitive type of using a capacitance coupling while an alternating current voltage is applied thereto, an electromagnetic type of sensing a selected position by a change in voltage while a magnetic field is applied thereto, and the like.
Among them, the resistive type and capacitive type touch screen sensors that are most extensively utilized recognize the touch by a change in electric contact or capacitance by using the transparent conductive layer such as the ITO film. However, since the transparent conductive layer has the high resistance of 100 ohms/square or more, the sensitivity is lowered when the display device is manufactured in a large scale, and as the size of the screen is increased, the cost of the ITO film is rapidly increased, and accordingly, it is not easy to perform commercialization thereof. In order to overcome this, there is an effort to implement enlargement by using a metal pattern having high conductivity.